2. Meaning of decimals: Divide the integer "1" into 10, 100, 1000 ... These fractions are one tenth, percentage and one thousandth respectively ... which can be expressed by decimals.

3. The decimal point has an integer part on the left and a decimal part on the right, followed by decimal, percentile and thousandth. ...

4. Classification of decimals: decimals, finite decimals, infinite cyclic decimals, infinite acyclic decimals,

Integers and decimals are numbers written in decimal notation.

6. decimal system. Attribute: Add 0 or remove 0 after the decimal point, and the size of the decimal point remains unchanged.

7. Move the decimal point to the right by one, two and three places ... The original number is enlarged by 10 times, 100 times and 1000 times respectively. ...

The decimal point is shifted to the left by one place, two places and three places ... The original number is reduced by 10 times, 100 times and 1000 times respectively. ...